Published 13 May 2024
Article by
3 min read
What is a 100 Hour Inspection?
A 100 hour inspection is a type of maintenance assessment for commercial aircrafts under 12,500 pounds. This is performed after every 100 hours of flight time by an FAA (Federal Aviation Administration) certified A&P (Airframe and/or Powerplant) mechanic or by the aircraft manufacturer. 100 hour inspections are compliance requirements under FAR’s (Federal Aviation regulations) 91.409 to ensure the safety and airworthiness of an aircraft.
Annual Inspection VS 100 Hour Inspection
100 hour inspections and annual inspections are often mistaken for one another. Though their general scope may be similar, there are a number of differences that separate the two. Below are key differences that distinguish annual inspections from 100 hour inspections:
WHO performs the inspection Only certified A&P mechanics with an inspection authorization can perform an annual inspection. However, no special inspection authorizations are necessary to conduct a 100 hour inspection.
WHEN to perform 100 hour inspections are performed after every 100 hours of flight time which means it may be performed more than once per year. Annual inspections, however, are required to be conducted every 12 calendar months regardless of total flight time.
WHAT the inspection covers Annual inspections and 100 hour inspections may have the same inspection scope and detail, but they differ in terms of regulatory requirements. Tasks such as inspecting components attached to the engine like propellers, magnetos and carburetor should be accomplished annually, while others like checking and adjusting fuel pressures and brakes are to be accomplished each 100 hours.
The goal of both annual inspections and 100 hour inspection is for aircrafts to fly safely and prevent any unwanted incidents that can endanger employees and customers.
What is Included in a 100-Hour Inspection Logbook Entry?
The inspection includes a review of the aircraft’s systems, components, and environment. It is important to document all work performed during the inspection in the aircraft’s logbook. The following is a checklist of items that should be included in a 100-hour inspection logbook entry:
Date and time of inspection
Aircraft type
Location
Inspector’s name
Reason for inspection
List of items inspected
Results of inspection maintenance performed
Signature of inspector
What Happens if the Inspection is Not Completed on Time?
A 100 hour inspection is a mandatory inspection procedure for most aircraft that must be completed every 100 hours of operation. If the inspection isn’t completed on time, the aircraft may not be flown. The aircraft may also be grounded if critical items are not completed on the inspection checklist. This can cause delays in upcoming flights and disrupt the travel plans of passengers.
What are the Consequences of Not Completing This Inspection?
The consequences of not completing a 100 hour inspection can be severe, including decreased aircraft performance, engine failure, and even aircraft crashes. Pilots are responsible for completing a 100 hour inspection and maintaining a 100 hour inspection logbook entry. A 100 hour inspection is required for many types of aircraft, including Cessna 172s.
